From mobile phones and tablets to big-screen TVs and digital signage, we live in a world filled with color screens, providing us with high-definition, vivid entertainment all the time.
As extreme weather events occur more frequently, countries around the world are setting carbon-neutral goals to combat climate change. We need more energy-saving and environmentally friendly displays to replace the power-hungry and high-emission LCD screens. So color e-paper is becoming the next big thing in making displays greener.
What is a color e-paper?
Color e-paper is a bistable color display that doesn't require power to stay active, but only uses energy to update the screen. This has significant power-saving advantages over traditional LCD screens.
E-papers form images by reflecting ambient light, which is different from light-emitting LCDs, so e-papers are easily readable under direct sunlight and do not emit blue light harmful to the eyes.
How does color e-paper work?
The most popular e-paper technologies on the market are electrophoretic (EPD) and cholesteric LCD (ChLCD).
EPD e-paper technology arranges charged ink capsules to create pixels, it is the most popular technology in black-and-white e-book readers. EPD mixes 4 ink colors or uses color filters to create around 4,000 colors at the most, which is a long way from the 16 million colors displayed on LCDs created by mixing 256 levels each of red, green, and blue. This makes it difficult for EPD e-paper displays to replace LCDs in practice.
IRIS Optronics uses 3 layers of ChLCD, each representing red, green, and blue, and has the bistable nature that exists between the two stable states:
- The planar state has the liquid crystal particles lined up uniformly to reflect specific wavelengths of light, to form unique colors.
- The focal conic state lines up the liquid crystal particles in a way to let light pass through, displaying the colors underneath.
By changing the 3 ChLCDs individually, we can display more than 16.78 million vibrant colors. It is the key color e-paper technology to replace light-emitting LCD and LED displays.
Advantages of color e-paper
Advantages of color e-paper displays include:
- Energy-saving and green - color e-paper only consumes power when refreshing the screen. In an update frequency of every 5 minutes, the e-paper display only requires 1% of the power used by an LCD. So e-paper displays have a very low carbon footprint.
- Eye care - unlike an LCD that actively emits light, including blue light, to display, e-paper reflects ambient light to form images, making it a more comfortable reading medium.
- Sunlight readable - unlike an LCD that needs to increase brightness to be legible in the sun, an e-paper display can provide vivid images by reflecting the sunlight, making it ideal for outdoor signage applications.
- Solar integration - while the ChLCD reflects different wavelengths of light, around 10-30% of the light passes through the display. By embedding solar cells under the screen, we create the Infinity Display that generates renewable energy to power itself.
Color e-paper applications
The environmentally friendly color e-paper has many applications to reduce energy consumption and carbon footprint:
- Public Transport - the green e-paper display is clearly visible in direct sunlight, and is very suitable for providing a low power consumption display outdoors, which can interact with the cloud to update real-time traffic information.
- Smart education - the reflective color e-paper can significantly cut down on the blue light damage to our eyes and provide a more comfortable reading environment. It combines with ebooks to reduce paper use, eliminate the heavy books to carry to school and reduce power consumption and carbon emission.
- Smart retail - the e-paper can be self-powered by solar energy to be untethered from the power grid, and display full-color digital posters anywhere outdoors. It can also work as a low-emission smart menu display indoors.
- Smart healthcare - an environmentally friendly, low emission smart display combined with a digital database to provide more accurate and up-to-date health records. The touch screen can synchronize data with the cloud to improve diagnosis efficiency and eliminate mistakes.
If you would like to know more about color e-paper applications, please get in touch with us.